Antineoplastons are peptides and amino acid derivatives isolated from urine and known for their antineoplastic effects in various cancers. These agents are currently being administered to HIV infected individuals for treatment of their lymphomas. In the course of treatment it was noticed that the HIV antigen levels decreased. It was therefore of interest to assess the anti-HIV effects of these agents. Three different antineoplastons, sodium phenyl acetylglutaminate (PG) sodium phenyl acetate (PN) and a mixture of PG and PN in the ratio of 1:4 were tested against HIV in target H9 and U937 cells. The concentrations used were 0.5, 0.1, 0.05, and 0.025 ug/ml. Preliminary results suggest that PN and PG at 0.05 and 0.1 ug/ml inhibit HIV replication by greater than 50% with minimal toxicity. We are at present evaluating other concentrations of these drugs for their effect on HIV replication.